Physicochemical studies are being continued on the creatine phosphokinase isoenzymes isolated from the brain, heart and skeletal muscle of terminal patients with duchenne (x-linked) progressive muscular dystrophy. Preliminary efforts at elucidating the total amino acid sequence of the crystalline dystrophic brain-type (from the brain) are being made, with initial efforts at deducing the amino acid sequence around its reactive thiol group and around the several loci which appear to differ from the normal human brain-type of creatin phosphokinase. Immunological procedures are being developed to facilitate the analyses of the isoenzyme distributions in normal human and in pathological tissues, in order to determine whether the various isoenzyme distributions of creatine phosphokinase may act as possible aids in the understanding of the biochemical and genetic basis of progressive muscular dystrophy. Adenylate kinase isoenzymes are in the process of being isolated from autopsy samples of muscle and liver, and from the erythrocyte of Duchenne dystrophics. These isoenzymes are to be characterized physically, chemically, and kinetically. The total amino acid dequence of the muscle-type will be initiated to compare against its normal counterpart, in order to deduce those mutational events, if any, which may be reflected in amino acid replacements. Anti-enzyme analyses are being undertaken to compare the isoenzyme distribution in the tissue of normal and dystrophic man at various stages of his development.